The Rang Ghar is a two-storied building which once served as the royal sports-pavilion where Ahom kings and nobles were spectators at games like buffalo fights and other sports at Rupahi Pathar (pathar meaning "field" in Assamese) - particularly during the Rongali Bihu festival in the Ahom capital of Rangpur.
It is said to be one of the oldest surviving amphitheaters in Asia, the building was first constructed during the reign of Swargadeo Rudra Singha with bamboo and wood. It was later rebuilt with brick by Swargadeo Pramatta Singha in AD 1744-1750.
The roof of the Rang Ghar is shaped like an inverted royal Ahom long boat. The base of the monument has a series of arched entrances, while atop the roof sits a decorative pair of carved stone crocodiles.
Many of the arched entrances have retained little more than their brick framework, with mere vestiges of sculptural adornments here and there. The Ahoms, who used special, thin, baked bricks, did not use cement but a paste of rice and eggs as mortar for their construction, a pulses called Maati Maah Assames and a fish named Borali Mach in Assamese. They also made use of powdered mixed lime and bricks to cover the surface of the inner walls. It is said that this layer of powder used to keep the inside of the Rang Ghar cool.
The adjoining field, known as Rupohi Pothar, wore a festive look when games like bull-fight, cock-fight, elephant fight, wrestling, etc., were held on different occasions during the Ahom rule. Rang Ghar, besides standing as the royal pavilion, also contributed in spreading the games to different parts of the kingdom and its neighbouring States.
About a kilometer to the northeast of the Rang Ghar is the Joysagar Pukhuri. This is a man-made tank, encompassing an area of about 120 bighas of land. It was dug in memory of Joymoti Konwari, mother of Rudra Singha - the most illustrious of the Ahom kings.